Medical navigation system with wirelessly connected, touch-sensitive screen

ABSTRACT

The invention relates to a medical system comprising an instrument, a data processing and image generating apparatus and an image display and control unit. Of these, the position acquisition apparatus is embodied to acquire a position and orientation of the instrument in relation to a reference coordinate system. The data processing and image generating apparatus is embodied to generate an image of a body part from currently recorded or stored data representing a body part, which image reproduces a view of the body part together with a representation of the position, and preferably also the orientation, of the instrument in such a way that an observer can gather the position and orientation of the instrument in the body part from the image of the body part. Here, according to the invention, the image display and control unit is wirelessly connected to the data processing and image generating apparatus, and comprises a display and input unit with a closed surface. On the closed surface of the display and input unit, control elements and a respective view of the body part are displayed during operation of the image display and control unit, together with a representation of the position, and preferably also the orientation, of the instrument. The image display and control unit is embodied to accept user inputs via displayed control elements and to transmit control signals to the data processing and image generating apparatus as a function of the respectively accepted user inputs.

The invention relates to a medical system comprising an instrument, aposition acquisition apparatus for the instrument and a data processingand image generating apparatus.

Using such a medical system, it is possible, for example, to acquire theposition and orientation of a medical instrument, and the position dataacquired thus can, for example, be assigned to a tomographic image of anobject or body part. The data processing and image generating apparatusis then able to generate an image of a body part from currently recordedor stored data representing a respective body part, which imagereproduces a view of the body part together with a representation of theposition and orientation of the instrument in such a way that anobserver can gather the position and orientation of the instrument inthe body part from the image of the body part. The position data,recorded for this purpose by the position acquisition apparatus,typically reproduce a position and orientation of a respectiveinstrument in relation to a reference coordinate system and cantherefore be transformed into a coordinate system underlying the imagedata by the data processing and image generating apparatus. Inprinciple, such medical systems are known and serve for so-callednavigation of surgical instruments, which are typically guided by hand.Therefore, an operator is able also to identify the position of theinstrument guided by him in a reproduction, for example a tomographicreproduction, of his patient and is therefore able to guide theinstrument to a target region or a target position in a targeted manner.By way of example, the employed position acquisition systems can beoptical, ultrasound-based or electromagnetic position acquisitionapparatuses. By way of example, electromagnetic position acquisitionapparatuses are known, in which a field generator generates analternating electromagnetic field and position sensors comprising coilsare provided on the instrument. Currents which depend on the alignmentof a respective coil in relation to the alternating electromagneticfield are induced in the coils by the alternating electromagnetic fieldof the generator. If a movable instrument is equipped with such positionsensors in the form of sensor coils, it is possible to determine alocation and position of the instrument relative to a reference sensor,which e.g. may likewise comprise coils. Here, the reference sensor, forexample as a patient localizer, is securely connected to a body part ofa patient (or else of a different object).

For navigation in body parts of a patient, the position and orientationof an instrument is typically acquired using such a position acquisitionapparatus and the position of the instrument is subsequently displayedin slice images of the body part obtained by tomography. In order forthis to work, the position data supplied by the position sensor of theinstrument must be transformed into coordinates of the tomographic imageof the patient. The position of the instrument, and preferably theorientation thereof as well, can then be depicted in slice images, orelse perspective representations, of the body part of a patient.

It is helpful to the operator if, for this, he is able to select therepresentation most expedient in each case; if, for example, he is ableto select different slice planes in order to be able in each case toselect a representation that is useful to him. Therefore, provision ismade for equipping such position acquisition apparatuses or dataprocessing and image generating apparatuses with input means which, forexample, allow the selection of a display format.

The invention is based on the object of improving such a system,especially in view of the operability by the operator.

According to the invention, this object is achieved by a medical systemcomprising an instrument, a data processing and image generatingapparatus and an image display and control unit. Of these, the positionacquisition apparatus is embodied to acquire a position and orientationof the instrument in relation to a reference coordinate system. The dataprocessing and image generating apparatus is embodied to generate animage of a body part from currently recorded or stored data representinga body part, which image reproduces a view of the body part togetherwith a representation of the position, and preferably also theorientation, of the instrument in such a way that an observer can gatherthe position and orientation of the instrument in the body part from theimage of the body part. Here, according to the invention, the imagedisplay and control unit is wirelessly connected to the data processingand image generating apparatus, and comprises a display and input unitwith a closed surface. On the closed surface of the display and inputunit, control elements and a respective view of the body part aredisplayed during operation of the image display and control unit,together with a representation of the position, and preferably also theorientation, of the instrument. The image display and control unit isembodied to accept user inputs via displayed control elements and totransmit control signals to the data processing and image generatingapparatus as a function of the respectively accepted user inputs.

By way of example, the display and input unit can be a touchscreen, i.e.a touch-sensitive screen, which also permits inputs via the screen. Thedisplay and input unit can also easily be used in an operating theateras a result of such a display and input unit being closed, as it is notso susceptible to contamination.

Since the image display and control unit is moreover connectedwirelessly to the data processing and image generating apparatus, theimage display and control unit can be placed or installed at in eachcase the most expedient location by the operator, or else it can beoperated hands-free. Thus, the operator can enter control inputsdirectly from the operation site or directly compare images on the imagedisplay and control unit with what is in front of his eyes in the caseof a patient.

In order to simplify the last aspect in particular, the medical systemis preferably embodied in such a way that the display and control unitdisplays a respective view of a body part with a 1:1 scale such thatdistances in a depicted slice plane of a body part are at leastapproximately identical to a distance along the slice plane in the bodypart itself. This not only permits a comparison between what theoperator has in front of his eyes in the case of the patient andcorresponding images, it also allows the operator to guide hisinstrument particularly precisely since the distances to be gatheredfrom the image display on the display and control unit preciselycorrespond to those by which he may, optionally, need to move theinstrument in order, for example, to arrive at a specific targetposition.

In this context, in addition to a respective position, and preferablyalso an orientation, of the instrument, it is particularly preferablefor the data processing and image generating apparatus to be furthermoreembodied to display in a respective view of a body part and a marking ofa further position and/or of a target region or target volume in thebody part.

Preferably, the data processing and image generating apparatus isembodied to access different data representing a respective body part,for example data obtained by computed tomography or data obtained bymagnetic resonance imaging. Moreover, the data processing and imagegenerating apparatus is accordingly embodied to generate an image, asdesired, which image is based on data obtained by computed tomography ordata obtained by magnetic resonance imaging. In this context, the imagedisplay and control unit is preferably embodied to display one or morecontrol elements, which serve for the selection to be made betweenvarious data representing a respective body part and, hence, thecorresponding image display. The image display and control unit isembodied to generate a control signal when an appropriate controlelement is actuated, which control signal causes the data processing andimage generating apparatus to generate an image on the basis of thecorrespondingly selected data representing a body part of the patient.

Moreover, the data processing and image generating apparatus ispreferably embodied to store a displayed image in such a way that it canbe recalled at a later time. This is therefore advantageous because,typically, the position of the instrument in the body part, and possiblythe body part as well, change or move over time such that, typically, acurrently reproduced image differs from an image reproduced at anearlier time. Therefore, it may be helpful to store an image at specifictimes, for example within the meaning of a screenshot. In this respect,the image display and control unit also preferably comprises acorresponding control element, wherein the image display and controlunit generates a control signal when said control element is actuated,which control signal causes the data processing and image generatingapparatus to store a respectively currently displayed image when thecontrol element is actuated.

Similarly, it may be desirable for the data processing and imagegenerating apparatus to be embodied to store an image sequence in thestyle of a film. In order to trigger this, the image display and controlunit also preferably comprises a corresponding control element, whereinthe image display and control unit generates a control signal when saidcontrol element is actuated, which control signal causes the dataprocessing and image generating apparatus to record an image sequencewithin the meaning of a film.

In accordance with a particularly preferred embodiment variant, thedisplay of the control element for triggering the recording of an imagesequence is modified in the case of the actuation which starts therecording of an image sequence. Thus, on the basis of the display of thecontrol element, the operator can himself identify that an imagesequence is currently being recorded. The image display and controlapparatus is furthermore preferably embodied for a second actuation ofthe control element for recording image sequences to again stop therecording of a respective image sequence. Preferably, the image displayand control unit once again generates the original display of thiscontrol element prior to triggering the recording of an image sequencein the case of the respective second actuation of the control element.

The invention is now intended to be explained in more detail on thebasis of an exemplary embodiment, with reference being made to thefigures. In detail:

FIG. 1 shows a medical system comprising an instrument, a positionacquisition apparatus for this instrument, a data processing and imagegenerating apparatus and an image display and control unit;

FIG. 2 shows a medical instrument and an associated position acquisitionapparatus comprising a field generator for an alternatingelectromagnetic field, and a position sensor fixed with respect to thepatient;

FIG. 3 shows an example of an image generated by the data processing andimage generating apparatus and displayed on the image display andcontrol unit, together with control elements likewise displayed on theimage display and control unit; and

FIG. 4 shows a display of control elements displayed on the imagedisplay and control unit.

FIG. 1 shows the components of a medical system, specifically aninstrument 16, a field generator 12 as part of a position acquisitionapparatus and a data processing and image generating apparatus 20, whichis connected to the field generator 12 and the instrument 16 via cables22 and 24, respectively. Moreover, FIG. 1 shows an image display andcontrol unit 30, which can easily be held by one or two hands and iswirelessly connected to the data processing and image generatingapparatus 20.

FIG. 2 shows, by way of a sketch, the head 10 of a patient in a sideview. The field generator 12 for generating an alternatingelectromagnetic field, which is to be acquired in the region of the headof the patient, is situated in the vicinity of the head 10. A positionsensor, which is fixed with respect to the patient, representing areference position sensor 14 or patient localizer is fastened to thehead 10 of the patient. The movable instrument 16 comprises a proximalend with a handle 18 and a distal end with an instrument positionsensor. The reference position sensor 14 and the instrument positionsensor respectively comprise one or more electrical coils as sensorcoils. The alternating electromagnetic field emanating from the fieldgenerator 12 during operation respectively induces a current in thecoils, the amplitude of which current depends on the relative positionand alignment of a respective sensor coil in relation to the fieldgenerator 12. Thus, it is possible, in a manner known per se, todetermine the relative position and alignment (orientation) of theinstrument position sensor in relation to the reference position sensor.

In order to use position values of an instrument, acquired by means of aposition acquisition system, for instrument navigation within themeaning of a respectively current position of an instrument beingdisplayed in slice images of a body part obtained e.g. by tomography,the position values supplied by the position sensor of the instrumentmust be transformed into a model coordinate system underlying atomographic image. A transformation prescription required for this isobtained in a manner known per se by means of a registration method. Byway of example, a surface of a body part is, to this end, scanned bymeans of a pointing or scanning instrument, and position values obtainedin the process are transferred with the smallest possible error to amodel surface derived from a tomographic or topographic image. Thescalings, rotations and/or translations or the like, which are requiredfor this transfer which is as accurate as possible, finally result inthe transformation prescription.

The data processing and image generating apparatus 20 can also be at adistance from the operation site, for example as part of a central datacenter.

The instrument 16 may be a surgical instrument or a microscope,endoscope or different movable instrument. The instrument 16 need notnecessarily be movable by hand, but may also be controlled by a robot.The image display and control unit 30 is embodied as an independentunit, which communicates wirelessly at least with the data processingand image generating apparatus 20, but can, for example, additionallyalso communicate with the instrument 16 in order to be able to control,in particular, the instrument 16 remotely by means of the image displayand control unit 30. By way of example, if the instrument 16 is anendoscope, the alignment of the endoscope optical unit can be controlledby means of the image display and control unit 30 to the extent thatsaid optical unit can be aligned by remote control. If the instrument 16is a microscope, the display and control unit 30 can be embodied tocontrol the focus control of the microscope or the overriding or settingof the autofocus control of the microscope remotely.

As can be gathered from FIG. 3 , the display and input unit 32 of theimage display and control unit 30 displays both at least one view 36 ofa body part and one or more control elements 34, and also informationicons 38. As already described above, the view 36 of a body part can begenerated a data of a body part obtained from the data processing andimage generating unit 20 by way of e.g. computed tomography or magneticresonance imaging. Additionally or alternatively, the depicted view canalso be a respectively current endoscope or microscope recording.Preferably, both views displayed from data obtained by tomography andviews recorded by means of an optical instrument, such as an endoscopeor a microscope, are displayed simultaneously. The view of a respectivebody part is preferably displayed with a scale of 1:1 such thatdistances on the plane of the display and input unit 32 of the imagedisplay and control unit 30 correspond to distances in the respectiveplane of the body part.

Both the position of a respective instrument 16 and also e.g. planninginformation, which is a result of preceding operation planning, arepreferably displayed in the respective views of a body part. By way ofexample, such planning information can be the marking of a target regionor a target volume in the respectively depicted view 36 of the bodypart. Other planning information can relate to the position andalignment of implants such as e.g. screws. If these are depicted in theview 36 of the body part, an operator can precisely align the realimplant during the operation on the basis of the depicted planninginformation in the view 36 of the body part.

Control elements 34 depicted on the display and input unit 32 can begathered from FIGS. 3 and 4 in an exemplary manner. By way of example, afirst control element 34.1 and a second control element 34.2 serve forselecting the data representing a respective body part.

Thus, by actuating the first control element 34.1, a user can cause theview 36 of the body part from data obtained by computed tomography to bedisplayed. By actuating the second control element 34.2, a user cancause the view 36 to be generated from data obtained by magneticresonance imaging. In each case, actuating a respective control element34.1 or 34.2 triggers the transmission of a corresponding control signalfrom the image display and control unit 30 to the data processing andimage generating unit. The latter then generates corresponding views 36of the body part and transmits these to the image display and controlunit 30, on the display and input unit 32 of which the correspondingview 36 is then depicted.

A third control element 34.3 enables snapshots to be recorded, either ofa respectively current view 36 of the body part only or else of thewhole display, including the control elements, depicted on the displayand input unit 32. If the third control element 34.3 is actuated by auser, the image display and control unit generates a control signalwhich prompts the data processing and image generating apparatus 20 tostore a corresponding view in such a way that it can be recalled at alater time.

Similarly, a fourth control element 34.4 enables the recording of animage sequence to be triggered, which, in the style of a film, is storedeither on the image display and control unit 30 itself or else on thedata processing and image generating apparatus 20. The recording of suchan image sequence is started with a respective first actuation of thefourth control element 34.4, while pressing the fourth control element34.4 a second time stops the recording of the image sequence again. Thedisplay of the fourth control element 34.4 is modified after the firstactuation thereof such that a user immediately knows that an imagesequence is currently being recorded. If this recording of an imagesequence is stopped again by a respective second actuation of the fourthcontrol element 34.4, the fourth control element 34.4 is once againdepicted in its original display format shown in FIGS. 3 and 4 .

Further control elements 34.6 and 34.7 serve, for example, for settingthe contrast (control element 34.6) and brightness (control element34.7) of the displayed view.

An eighth control element enables a reset. By actuating the eighthcontrol element 34.8, the original settings are restored.

Using a ninth control element 34.9, positions can be marked in thedepicted view 36 of the body part. A tenth control element 34.10 enablesswitching between different display scales, wherein a display scale of1:1 is preferred.

Moreover, the image display and control unit 30 allows switching betweenvarious instruments that are connected wirelessly to the image displayand control unit 30, for example switching between endoscope andsurgical instrument.

However, switching between various instruments can also be brought aboutautomatically by an operator picking up a respective instrument. In thiscase, the respective instrument currently in use is displayed on thedisplay and input unit 32 by an information icon such as the icon 38.1.

From the interaction between the image display and control unit 30 andan instrument 16 in the form of an endoscope, a particularlyadvantageous application emerges to the extent that, for example, theattention can be focused on image points or positions, determined by theendoscope, in a two-dimensional plane or in a three-dimensional space(i.e., for example, these can be brought into the center of theendoscope image). A respective position can be stored by actuating acorresponding control element, either on the display and input unit 32of the image display and control unit or else on the endoscope itself. Aplurality of such positions can subsequently be connected to one anotherin a polygonal train which, for example, describes a body cavity or elsea cavity—more precisely: the contour thereof—artificially created by anoperation (e.g. after removing a tumor). Such a polygonal train can thenserve as a template for cutting out body tissue parts, which for exampleshould serve for filling the artificially created cavity and are takenfrom a different position of the body of a patient.

Instead of generating a polygonal train from individual body positionsdriven to by means of the endoscope, provision can also be made forcontinuous tracking of the alignment of the endoscope in order thus togenerate a continuously recorded template. However, incorrect alignmentsof the endoscope while recording the template would also be recorded inthe process.

Moreover, the image display and control unit 30 itself also allows auser to mark individual positions or else trace out depicted contours onthe view 36 of a body part, for example by means of an input stylus, inorder thus to generate the corresponding position data for generating atemplate.

A further function offered by the image display and control unit 30 liesin the sensing of landmarks on the view 36 of the body part in orderthus, for example, to bring various displays, such as e.g. an endoscopicrecording and a view generated from data obtained by tomography, inline, to corresponding landmarks are assigned to one another in thevarious representations.

Provision can also be made for the image display and control unit 30 tobe able to be connected to various instruments and/or data processingand image generating apparatuses 20 such that a plurality of operationscan be tracked by means of a single image display and control unit 30 byswitching between different data processing and image generatingapparatuses 20.

Basic settings for various users of an image display and control unit 30and/or basic settings for various image display and control units 30 canbe stored either on a respective image display and control unit 30 orelse on a corresponding data processing and image generating apparatus20, in particular if the latter is implemented in the form of a centralserver or data center. This renders it possible, particularly on acentral data processing and image generating apparatus as well, to storebasic settings for various users such that respectively different imagedisplay and control units 30, even with different operating systems, canbe used without a user having to adapt himself to in each case verydifferent representation manners or pre-settings. Rather, therepresentation manners and pre-settings can respectively be realized tobe the same, or at least similar, on various image display and controlunits, independently of a respectively specific image display andcontrol unit 30 and the specific operating systems thereof.

Moreover, it is possible for data to be stored in a respective imagedisplay and control unit 30, which data either partly or completelydescribe a respective medical system. These can include instrumentdescriptions, as well as descriptions of the position acquisitionapparatus or else of the data processing and image generating apparatus.Such data can be stored permanently in a respective image display andcontrol unit 30, or else can only be transmitted with the start of arespective application, for example from a corresponding data processingand image generating apparatus 20 to a respective image display andcontrol unit 30. In the latter case, different image display and controlunits 20 of different types or with different equipment can also, inparticular, easily be replaced for one another.

Conversely, data which describe individual image display and controlunits 30, optionally also individually for different users of arespective image display and control unit 30, can also be stored in arespective data processing and image generating apparatus 20.

In one extreme case, the complete data processing and image generatingapparatus 20 can also be integrated in a respective image display andcontrol unit 30.

Conversely, it is also possible for all essential information to bestored in the data processing and image generating apparatus 20 suchthat, firstly, the image display and control unit 30 can be kept quitesimple and, secondly, all essential information is kept availablecentrally and therefore kept available for other users or image displayand control units 30 as well. By way of example, if the wholerepresentation on a respective display and input unit 32 of an imagedisplay and control unit 30, including the positions and display formatsof the control elements, is predetermined by a corresponding dataprocessing and image generating apparatus 20, it may be sufficient for arespective image display and control unit 30 only to generate onecontrol signal when a corresponding, depicted control element on thedisplay and input unit 32 is touched, which control signal reflects therespectively touched position on the display and input unit 32. Thisinformation is then sufficient for the data processing and imagegenerating apparatus 20 to identify which control element was actuatedon the image display and control unit 30 or which position was marked onthe displayed view 36 of a body part.

By virtue of, thus, all essential functionalities of the image displayand control unit 30 being in fact provided and executed by the dataprocessing and image generating apparatus 20, it is possible to providesimultaneous powerful functionalities and provide simple, in particularsmall and light, image display and control units 30. Since, as explainedabove, the data processing and image generating apparatus 20 also neednot be in the direct vicinity of a user or operator, but may for examplebe realized in a central data center, a user or operator can, within hiswork surroundings, concentrate fully on his instruments and optionallyresort to the image display and control unit for support. Since thelatter optionally may also serve as remote control for the correspondinginstruments of the user or operator (see above), this greatly simplifiesthe work of the user and operator at his workplace—for example in theoperating theater.

In particular, an image display and control unit 30 described herepermits instrument-centered work of the user or operator, during whichthe latter can wholly concentrate on his instruments and is largelyunburdened from further technical burdens.

LIST OF REFERENCE SIGNS

-   10 Patient head-   12 Field generator-   14 Position sensor fixed with respect to the patient-   16 Movable instrument-   18 Handle of the movable instrument-   20 Data processing and image generating apparatus-   22 Connecting cable-   24 Instrument cable-   30 Image display and control unit-   32 Display and input unit-   34 Control element-   36 View of a body part-   38 Information icon

1. A medical system comprising an instrument (16), a positionacquisition apparatus (12, 14) for the instrument, a data processing andimage generating apparatus (20) and an image display and control unit(30), of which the position acquisition apparatus (12, 14) is embodiedto acquire a position of the instrument (16) in relation to a referencecoordinate system and of which the data processing and image generatingapparatus (20) is embodied to generate an image of a body part fromcurrently recorded or stored data representing a body part, which imagereproduces a view (36) of the body part together with a representationof the position of the instrument (16) in such a way that an observercan gather the position of the instrument (16) in the body part from theimage of the body part, wherein the image display and control unit (30)is wirelessly connected to the data processing and image generatingapparatus (20), and comprises a display and input unit (32) with aclosed surface, on which control elements (34) and a respective view(36) of the body part are displayed during operation, together with arepresentation of the position of the instrument (16), wherein the imagedisplay and control unit (30) is furthermore embodied to accept userinputs via displayed control elements (34) and to transmit controlsignals to those of the data processing and image generating apparatus(20) as a function of the respectively accepted user inputs.
 2. Themedical system of claim 1, characterized in that, in addition to arespective position of the instrument, the data processing and imagegenerating apparatus (20) is furthermore embodied to display in arespective view (36) of a body part a marking of a further positionand/or of a target region or target volume in the body part.
 3. Themedical system of claim 1, characterized in that the display and inputunit (32) is embodied to display a respective view (36) of the body partwith a 1:1 scale such that distances in a depicted slice plane of a bodypart are at least approximately identical to a distance along the sliceplane in the body part itself.
 4. The medical system of claim 1,characterized in that the data processing and image generating apparatus(20) is embodied to access different data representing a respective bodypart, wherein the data processing and image generating apparatus (20) isaccordingly embodied to generate an image, as desired, which image isbased on respectively selected data representing a respective body part,and the image display and control unit is embodied to (30) display oneor more control elements (34), which permit a selection to be madebetween various data representing a respective body part and, hence, thecorresponding image display, wherein the image display and control unit(30) generates a control signal when an appropriate control element (34)is actuated, which control signal causes the data processing and imagegenerating apparatus (20) to generate an image on the basis of thecorrespondingly selected data representing a body part of the patient.5. The medical system of claim 1, characterized in that the dataprocessing and image generating apparatus (20) is embodied to store adisplayed image in such a way that it can be recalled at a later time,and in that the image display and control unit (30) comprises acorresponding control element (34), wherein the image display andcontrol unit (30) generates a control signal when said control elementis actuated, which control signal causes the data processing and imagegenerating apparatus (20) to store a respectively currently displayedimage when the control element (34) is actuated.
 6. The medical systemof claim 1, characterized in that the data processing and imagegenerating apparatus (20) is embodied to store an image sequence in thestyle of a film and in that the image display and control unit (30)comprises a corresponding control element (34), wherein the imagedisplay and control unit (30) generates a control signal when saidcontrol element is actuated, which control signal causes the dataprocessing and image generating apparatus to record an image sequencewithin the meaning of a film.
 7. The medical system of claim 6,characterized in that the image display and control unit (30) isembodied to modify a display of the control element (34) for triggeringthe recording of an image sequence in the case of an actuation whichstarts the recording of an image sequence.
 8. The medical system ofclaim 6, characterized in that the image display and control unit (30)is embodied in such a way that it generates a control signal in the caseof a second actuation of the control element (34) for recording imagesequences, which control signal causes the data processing and imagegenerating apparatus (20) to stop the recording of a respective imagesequence.
 9. The medical system of claim 7, characterized in that theimage display and control unit (30) is embodied in such a way that, inthe case of the respective second actuation of the control element (34),it once again brings to display the original display of this controlelement (34) prior to triggering the recording of an image sequence.